Motor drive unit

ABSTRACT

A motor assembly for driving a pump or rotary device features a power plane with a circular geometry to be mounted inside a space envelope having a similar circular geometry formed on an end-plate between an inner hub portion and a peripheral portion that extends circumferentially around the space envelope of the end-plate. The power plane is a multi-layer circuit board or assembly having: a power layer with higher temperature power modules for providing power to a motor, a control layer with lower temperature control electronics modules for controlling the power provided to the motor, and a thermal barrier and printed circuit board layer between the power layer and the control layer that provides electrical connection paths between the power modules of the power plane and the control electronics modules of the control layer, and also provides insulation between the power layer and the control layer.

CROSS REFERENCE TO RELATED APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet of the present applicationare hereby incorporated by reference in their entireties under 37 CFR1.57.

NAMES OF PARTIES TO JOINT RESEARCH AGREEMENT

The subject matter disclosed in this application was developed and theclaimed invention was made by, or on behalf of, ITT Corporation and/orthe University of Nottingham, which are parties to a joint researchagreement that was in effect on or before the effective filing date ofthe claimed invention. The claimed invention was made as a result ofactivities undertaken within the scope of the joint research agreement.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This application relates to a technique for increasing the power densityof the electronics of a variable frequency drive and reducing thesensitivity of electronics of a variable frequency drive to hightemperatures for the purpose of installing the variable speedelectronics inside a motor assembly; and more particularly to atechnique for reducing the sensitivity of electronics of a variablefrequency drive to high temperatures, e.g., using a uniquely designedmid-plate and end-plate.

2. Brief Description of Related Art

In the prior art, it is known that electronics of a variable frequencydrive are typically sensitive to high temperatures, and can improperlyoperate or fail prematurely if operated at their maximum rating whencombined with a motor assembly, and that the electronics need a sealedenclosure contained within the motor envelope that protects theelectronics from both harsh environments and excessive heat. The motornormally operates at a temperature much higher than safe electronicoperation. When one combines these two devices, the losses (heat)created from the motor's operation will cause a high temperaturecondition, that is unhealthy to the operation of the variable frequencydrive.

To put this into some perspective, a premium efficient motor may be94-95% efficient. Thus, 5-6% of its rating is wasted from a loss of heatmeasured in relation to watts loss or heat. For a variable frequencydrive, it might be 96-97% efficient. Therefore, in a 50 HP system, theheat loss calculation may take the form of: 50 HP×746 watts/HP=37,300watts, and 37,300 watts×10%=3,730 watts of waste heat.

Specifically, the 4% overall drive losses would split up as follows:approximately 85% in the power modules contained in the end-plate, 10%in the power quality filter, and 6% in the rest of the motor.

In view of this, there is a need in the art to provide a better way toreduce the sensitivity of the electronics of the variable frequencydrive to high temperatures, so as to eliminate or reduce substantiallythe improper operation or failure prematurely of such electronics ofsuch a variable frequency drive if operated at their maximum rating.

SUMMARY OF THE INVENTION

An objective of the present invention is to install an electronicvariable frequency drive inside the same size envelope as a standardNational Electrical Manufacturers Association (NEMA) or InternationalElectrotechnical Commission (IEC) rated motor of the same power rating,thereby allowing variable speed operation of the motor and any pump orrotary device it controls.

The Basic Apparatus

According to some embodiments, the present invention may take the formof apparatus, e.g., such as a motor assembly for driving a pump orrotary device, having at least one plate having two sides, one sidehaving a central portion, an intermediate portion and a peripheralportion.

The central portion may include, or be configured with, an opening toreceive and arrange the at least one plate in relation to a rotor, e.g.,of a motor drive the pump or rotary device.

The intermediate portion may be configured between an innercircumference of the central portion and the peripheral portion, and mayinclude a multiplicity of internal radial cooling fins extending fromthe inner circumference of the central portion and diverging outwardlytowards the peripheral portion to transfer heat from the central portionto the peripheral portion allowing for internal conduction heatcapability.

The peripheral portion may include an outer circumferential surfacehaving a multiplicity of external radial cooling fins divergingoutwardly away from the plate to transfer the heat to surrounding airallowing for external convection heat capability.

The at least one plate may be, or take the form of, a mid-plate, anend-plate, or a combination thereof, that form part of the pump orrotary device, consistent with that set forth herein.

Mid-Plate Embodiments

For example, the at least one plate may include, or take the form of, amid-plate having a bearing housing flange portion configured to receivea motor bearing assembly, and also configured with the opening toreceive the motor rotor shaft.

Mid-plate embodiments may also include one or more of the followingfeatures:

The apparatus may be, or take the form of, the motor assembly fordriving the pump or rotary device, e.g., having a combination of therotor and the motor bearing assembly having a bearing assembly arrangedon the rotor.

The other of the two sides may be a smooth side having a correspondingintermediate portion with no internal or external cooling fins.

The motor assembly may include an insulation layer arranged in relationto the mid-plate, and configured to reduce the rate of heat transfer,including all forms of heat transfer from conduction, convection andradiation. By way of example, the insulation layer may be made of mica.

The motor assembly may include a power plane having electricalcomponents, including electronics of a variable frequency drive, and themid-plate may be configured so that the smooth side is facing the powerplane

In operation, the heat may be transferred via conduction from the rotorthrough the mid-plate and the internal radial cooling fins to theexternal radial cooling fins, and may also then be transferred viaconvection from the external radial cooling fins to the surrounding air.The mid-plate may be configured to absorb the heat both via conductionfrom the rotor through the bearing assembly, and via convection throughthe external radial cooling fins located in the air chamber of themotor, including the heat generated from the motor from electrical andmechanical losses, including from either motor end windings, resistiveor eddy currents, or both, that cause the rotor to directly conduct heatas well as to release the heat into an air chamber of the motor.

The mid-plate may be configured to provide a thermal path either fromthe motor end-windings to the airflow on the outside of a stator, orfrom the rotor to the ambient through the bearing assembly, or both.

The motor assembly may include front and rear grease retainer configuredon each side of the motor bearing housing.

The motor assembly may include an insulating gasket assembly configuredon the mid-plate to minimize thermal contact between the mid-plate andan end-plate.

By way of example, the mid-plate may be made of copper, aluminum or castiron.

The mid-plate may include an outside insulation layer that limits heatflow from a mid-plate heat sink to a power converter area having a powerplane and limits heat into an end-plate electronics area that form partof the end-plate.

The internal radial cooling fins of the mid-plate may be configured onand about the intermediate portion substantially uniformly andequidistantly spaced from one another.

The external radial cooling fins of the mid-plate may be configured onand about the peripheral portion uniformly and equidistantly spaced fromone another.

By way of example, the mid-plate may have more external radial coolingfins then the internal radial cooling fins, including more than twice asmany.

End-Plate Embodiments

By way of further example, the at least one plate may include, or takethe form of, an end-plate, where the opening of the central portion isconfigured to receive and engage the motor rotor shaft.

End-plate embodiments may also include one or more of the followingfeatures:

The other of the two sides may be a smooth side having a correspondingintermediate portion with no internal or external cooling fins.

The apparatus may include a motor assembly having a power plane withelectrical components, including electronics of a variable frequencydrive, the end-plate may be configured with an electronics housingchamber, and the power plane may be configured within the electronicshousing chamber so that the smooth side is facing the power plane.

The motor assembly may include an electronics module arranged betweenthe power plane and the smooth side of the end-plate within theelectronics housing chamber.

The external radial cooling fins of the end-plate may be configured onand about the intermediate portion substantially uniformly andequidistantly spaced from one another.

The external radial cooling fins of the end-plate may be configured onand about the peripheral portion uniformly and equidistantly spaced fromone another.

Power Plane Embodiments

Apparatus, e.g., such as a motor assembly for driving a pump or rotarydevice, may include a power plane with a circular geometry to be mountedinside a space envelope having a similar circular geometry formed on anend-plate between an inner hub portion and a peripheral portion thatextends circumferentially around the space envelope of the end-plate.The power plane may be a multi-layer circuit board or assembly having:

-   -   a power layer with at least one higher temperature power module        for providing power to a motor,    -   a control layer with at least one lower temperature control        electronics modules for controlling the power provided to the        motor, and    -   a thermal barrier and printed circuit board layer between the        power layer and the control layer that provides electrical        connection paths between the power modules of the power plane        and the control electronics modules of the control layer, and        also provides insulation between the power layer and the control        layer.    -   Power plane embodiments may also include one or more of the        following features:    -   The power plane may be configured to do at least the following:        -   allow the mounting of the at least one power module and the            at least one control electronics modules on opposite sides            of a thermal barrier,        -   provide the electrical connection paths for interconnecting            together the at least one power module and the at least one            control electronics modules, as well as for interconnecting            input/output power connections and the at least one power            module and the at least one control electronics modules, and        -   insulate and/or direct heat emitted from one or more of the            at least one power module, the at least one control            electronics modules and a shaft of the motor to the outer            diameter of the power plane where there is a higher air            flow.

The power plane may be configured as a doughnut shaped power planeprinted circuit board or assembly in order to fit in the space envelopeof the end-plate for providing a maximum space for mounting the powerlayer and the control layer, and to allow the shaft of the motor rotorto pass through to drive a cooling fan.

The power layer may be configured with higher temperature power modules;the control layer may be configured with lower temperature controlelectronic modules and components and power quality filter components;and the thermal barrier and printed circuit board layer may beconfigured from a material having a structural thickness and strength tomount the control layer on one side and the power layer on an oppositeside, the material configured to provide insulation to reduce thetransfer of heat between the power layer and the control layer.

The thermal barrier and printed circuit board layer may be constructedof a laminated material, including fiberglass, that provides structuralstrength and acts as an insulator for separating hotter powersemiconductors of the power layer from cooler and sensitive controlelectronics and power quality capacitors of the control layer.

The power layer may include a circular power modules arrangementconfigured on one side of the thermal barrier and printed circuit boardlayer to couple to power plane low inductance input and integratedoutput connections, e.g., attached to an intermediate portion of theend-plate.

The at least one power module may include matrix converter power modulesconfigured as part of a matrix converter to receive AC input signalinghaving an AC waveform with a voltage and frequency and provide convertedAC signaling having a converted AC waveform with a converted voltage andfrequency to drive the motor.

The control layer may include at least one power quality filtercomponent configured to reduce the level of electrical noise andharmonic distortions.

The at least one power quality filter component may be attached directlyonto the thermal barrier and printed circuit board layer and configuredphysically close or next to the matrix converter to reduce the amount ofdistortions emitted from matrix converter electronics in the matrixconverter.

The at least one power module may include power semiconductor modules;the at least one control electronics module may include power qualitycapacitors; and the power plane may include low inductance andresistance inputs configured between the power semiconductor modules andthe power quality capacitors in order to reduce switching stress andelectromagnetic interference.

The power plane may include one or more compact power quality filtersintegrated therein.

The power plane may include a built-in power quality filter configuredto produce minimal harmonic distortion, and protect the variable speeddrive from most power quality abnormalities.

The power plane may be configured to combine both power and controlcircuits or circuitry into one integrated printed circuit boardconfiguration for ease of assembly and compactness in size.

The power plane may include a combination of one or more of thefollowing: current sensors, at least one gate driver, a power supply, aclamp circuit, power semi-conductor modules and power qualitycapacitors; and the electrical connection paths may be configured tointerconnect input/output power connections and the combination of oneor more of the current sensors, the at least one gate driver, the powersupply, the clamp circuit, the power semi-conductor modules and thepower quality capacitors.

The motor assembly may include the end-plate; the inner hub portion maybe configured to receive the shaft of the motor rotor; and theperipheral portion may include heat fins configured to dissipate awayfrom the end-plate heat generated by the at least one power module andthe at least one control electronic module.

The motor assembly may include a motor casing configured to be utilizedas a heat sink to allow a compact size and thermally optimized operationof the power plane.

The motor assembly may include, or takes the form of, a rotary device orpump, e.g., having the end-plate with the power plane arranged therein.

Advantage

Overall, the present invention provides a better way to increase thepower density of variable frequency electronics and reduce thesensitivity of the electronics of a variable frequency drive to hightemperatures for the purpose of installing the variable speedelectronics inside a motor assembly; so as to eliminate or reducesubstantially the improper operation or failure prematurely of suchelectronics of such a variable frequency drive if operated at theirmaximum rating.

BRIEF DESCRIPTION OF THE DRAWING

The drawing includes the following Figures, which are not necessarilydrawn to scale:

FIG. 1 is an exploded view of apparatus, e.g., in the form of a motorassembly for driving a pump or rotary device, according to someembodiments of the present invention.

FIGS. 2A and 2B are cross-sectional views of part of a motor assembly,e.g., similar to or like that shown in FIG. 1.

FIGS. 3A-3B show a mid-plate according to some embodiments of thepresent invention—including FIG. 3A showing a perspective view of amotor side of the mid-plate, and FIG. 3B showing a perspective view of apower plane side of the mid-plate shown in FIG. 3A, e.g., forconfiguring in the motor assembly shown in FIG. 1 or 2A-2B, according tosome embodiments of the present invention.

FIGS. 4A-4B show an end-plate according to some embodiments of thepresent invention—including FIG. 4A showing a perspective view of a fanside of the end-plate, and FIG. 4B showing a perspective view of amid-plate side of the end-plate shown in FIG. 4A, e.g., for configuringin the motor assembly shown in FIG. 1 or 2A-2B, according to someembodiments of the present invention.

FIG. 5A shows a motor assembly having labeled and identified a motorframe, a mid-plate, an end-plate, a terminal box and a fan; FIG. 5Bshowing a prospective view of a motor assembly that includes a partialexploded view of the terminal box; FIG. 5C showing a prospective view ofa motor assembly that includes a partial exploded view of a motor andmid-plate combination, an end-plate, a fan and a shroud; and FIG. 5Dshowing an exploded view of a self-contained drive module assembly,e.g., all according to some embodiments of the present invention.

FIG. 6A shows a diagram of a bi-directional switch for implementing somepart of the power functionality, e.g., of the power plane, according tosome embodiments of the present invention, and FIG. 6B shows an exampleof a bi-directional switch power module for implementing some part ofthe power functionality, according to some embodiments of the presentinvention.

FIG. 7 shows a photograph of a motor end-plate having a power plane witha matrix converter arranged therein, e.g., configured with an example ofa main power supply, a controller, a gate drive layer, clamp capacitors(CC) and input filter capacitors (IFC), according to some embodiments ofthe present invention.

FIG. 8 shows a typical graph of a 40 HP EMD (aka a “variable frequencyor speed drive) input voltage and current waveform.

FIG. 9A shows a diagram of a top view of an end-plate having a spaceenvelope formed therein between an inner hub portion and a peripheralportion, that includes arrows representing heat flowing away from theinner hub portion and towards the peripheral portion, e.g., whenoperating according to some embodiments of the present invention; andFIG. 9B shows a diagram of a side cross-sectional view of the end-platein FIG. 9A having corresponding arrows representing heat flowing awayfrom the inner hub portion and towards the peripheral portion of theend-plate, when operating according to some embodiments of the presentinvention.

FIG. 10A shows an end-plate having an example of one possible clampresistor implementation, according to some embodiments of the presentinvention; and FIG. 10B shows a donut shaped power plane printed circuitboard layer, e.g., including an example of connections to three shuntresistors and gate driver connections, according to some embodiments ofthe present invention.

FIG. 11 is an exploded view of apparatus, e.g., in the form of a motorassembly for driving a pump or rotary device, according to someembodiments of the present invention.

FIGS. 12A and 12B are cross-sectional views of part of a motor assembly,e.g., similar to or like that shown in FIG. 11.

FIGS. 13A(1), 13A(2) and 13B show a mid-plate according to someembodiments of the present invention—including FIG. 13A(1) showing aperspective view of a motor side of the mid-plate, and FIG. 13A(2)showing a perspective view of a power plane side of the mid-plate shownin FIG. 3A(1), e.g., for configuring in the motor assembly shown in FIG.11 or 12A and 12B, according to some embodiments of the presentinvention; and FIG. 13B showing one side of a mid-plate, e.g., forconfiguring in the motor assembly shown in FIGS. 11 or 12A and 12B,according to some embodiments of the present invention.

FIGS. 14A-14B show an end-plate according to some embodiments of thepresent invention—including FIG. 14A showing a perspective view of a fanside of the end-plate, and FIG. 14B showing a perspective view of amid-plate side of the end-plate shown in FIG. 14A, e.g., for configuringin the motor assembly device shown in FIGS. 11 or 12A and 12B, accordingto some embodiments of the present invention.

FIG. 15 shows a photograph of a motor assembly having labeled andidentified a motor frame, a mid-plate, an end-plate, and a fan, e.g.,according to some embodiments of the present invention.

FIG. 16 shows a photograph of a motor end-plate having a power planearranged therein and configured with a printed circuit board (PCB) and amatrix converter, according to some embodiments of the presentinvention.

FIG. 17A shows a diagram of a top view of an end-plate having a spaceenvelope formed therein between an inner hub portion and a peripheralportion, that includes arrows representing heat flowing away from theinner hub portion and towards the peripheral portion, e.g., whenoperating according to some embodiments of the present invention; FIG.17B shows a diagram of a side cross-sectional view of the end-plate inFIG. 17A having corresponding arrows representing heat flowing away fromthe inner hub portion and towards the peripheral portion of theend-plate, when operating according to some embodiments of the presentinvention; and FIG. 17C shows a diagram of a side cross-sectional viewof the end-plate in FIG. 17B having various modules and componentsarranged in the space envelope, including a circular power modulesarrangement, power plane low inductance input and integrated outputconnections, low temperature electronic components, e.g., mounted on thepower plane, and power quality filter capacitors, according to someembodiments of the present invention.

FIG. 18A showing a power modules layout that forms part of a motorassembly, all according to some embodiments of the present invention.

FIG. 18B shows a photograph of a final assembly of a matrix converterarranged in an end-plate, e.g., having a power plane circuit board witha gate driver power supply, a clamp circuit control, input filtercapacitors clamp capacitors and control cards assembled thereon,according to some embodiments of the present invention.

The drawing includes examples of possible implementations; and the scopeof the invention is not intended to be limited to the implementationsshown therein. For example, the scope of the invention is intended toinclude, and embodiments are envisioned using, other implementationsbesides, or in addition to, that shown in the drawing, which may beconfigured within the spirit of the underlying invention disclosed inthe present application as a whole.

DETAILED DESCRIPTION OF THE INVENTION The Basic Apparatus 10

FIGS. 1 and 11 show an apparatus generally indicated as 10, 10′, e.g.,that may include, or take the form of, a motor assembly 10 for driving apump or rotary device (not shown). The motor assembly 10 includes amotor M having a motor frame MF with a stator J (see FIG. 2A, 2B; 12A,12B) arranged therein, a rotor R coupled to the motor M, a mid-plate Ehaving a bearing housing flange portion A (see FIG. 2A, 2B; 12A, 12B), arear motor bearing assembly generally indicated as H having a bearingassembly BA, front B and rear C grease retainers, a fan F, an integratedinsulated layer G, a gasket assembly GA (FIG. 11), an end-plate D, apower plane P (FIG. 2A, 2B, 11, 12A, 12B) and a shroud S. The motorframe MF also includes a terminal box TB, e.g., as shown in FIGS. 1 and11. The power plane P may be configured to include electronics, e.g.,including a variable frequency drive, configured for controlling theoperation of the motor M, which in turn is used for driving the pump orother rotary device. The power plane P is described in further detail,e.g., in relation to that shown in FIGS. 6A through 10B, as well asFIGS. 16, 17C, 18A and 18B.

By way of example, and according to some embodiments of the presentinvention, the motor assembly 10 may feature, or be configured with, anew and unique mid-plate E, end-plate D, ora combination thereof, e.g.,consistent with that set forth below in relation to FIGS. 3A-4B.

FIGS. 3A-3B and 13A(1)-13B: The Mid-plate E

For example, FIGS. 3A-3B and 13A(1)-13B shows the mid-plate E, E′, E″,each mid-plate having two sides S₁, S₂, including a motor side S₁ havinga central portion E₁, an intermediate portion E₂, and a peripheralportion E₃.

The intermediate portion E₂ may be configured between the innercircumference E₁′ of the central portion E₁ and the peripheral portionE₃, consistent with that shown in 3A and 13A(1). The intermediateportion E₂ may include a multiplicity of internal radial cooling finsE₂′ extending from part of the inner circumference E₁′ of the centralportion E₁ and diverging outwardly (e.g., away from one another) towardsthe peripheral portion E₃ to transfer heat from the central portion E₁to the peripheral portion E₃ allowing for internal conduction heatcapability.

The peripheral portion E₃ may include an outer circumferential surfaceE₃′ having a multiplicity of external radial cooling fins E₃″ divergingaway from the peripheral portion E₃ to transfer the heat to surroundingair allowing for external convection heat capability.

The central portion E₁ may include the bearing housing flange portion A(see also FIGS. 1-2A, 2B; 11, 12A, 12B) configured to receive the motorbearing assembly H, and also configured with the opening O to receiveand engage the rotor R. The motor assembly 10 may include a combinationof the rotor R and the motor bearing assembly H (FIGS. 1-2A, 2B; 11,12A, 12B) arranged on the rotor R.

FIG. 3B, 13A(2) shows a power plane side S₂ of the two side, e.g., thatmay be a smooth side having a corresponding intermediate portionE_(2, 2) with no cooling fins.

The motor assembly 10 may include the thermal insulator TI (FIG. 1), orthe insulation layer G (FIGS. 12A-12B), arranged in relation to themid-plate E and the end-plate D, and configured to reduce the rate ofheat transfer, including all forms of heat transfer from conduction,convection and radiation.

FIG. 13B shows an alternative embodiment of a mid-plate generallyindicated as E″. Similar elements in FIGS. 13A, 13B are labeled withsimilar reference labels. By way of example, one difference between themid-plates E′ and E″ in FIGS. 13A, 13B respectively is that themid-plate E′ includes the bearing housing flange portion A, e.g., alsoshown in FIG. 3A, while the mid-plate E″ does not. Embodiments areenvisioned, and the scope of the invention is intended to include,mid-plates having such a bearing housing flange portion A, as well asembodiments that do not.

Consistent with that shown in FIG. 3A, the internal radial cooling finsE₂′ may be configured on and about the intermediate portion E₂substantially uniformly and equidistantly spaced from one another. Theexternal radial cooling fins E₃″ may be configured on and about theperipheral portion E₃ substantially uniformly and equidistantly spacedfrom one another. By way of example, and consistent with that shown inFIGS. 3A-3B, the mid-plate E may be configured with more external radialcooling fins E₃″ than the internal radial cooling fins e.g., includingthan more than twice as many more. In FIG. 3A, the mid-plate E is shownwith 30 (e.g. compare mid-plate E′ in FIG. 13A(1) with 36) internalradial cooling fins E₂′ that are substantially uniformly andequidistantly spaced from one another. In FIG. 3A, the mid-plate E(1) isshown with 48 (e.g. compare mid-plate E′ in FIG. 13A(1) with 94)external radial cooling fins E₃″ that are substantially uniformly andequidistantly spaced from one another. However, the scope of theembodiment is not intended to be limited to the number of the internalradial cooling fins E₂′, the number of the external radial cooling finsE₃″, or numerical relationship between the number of the internal radialcooling fins E₂′ and the number of the external radial cooling fins E₃″.For example, embodiments are envisioned, and the scope of the inventionis intended to include, implementations in which the number of theinternal radial cooling fins E₂′ and the number of the external radialcooling fins E₃″ is greater or less than that shown in FIGS. 3A-3B.Embodiments are also envisioned, and the scope of the invention isintended to include, implementations in which the numerical relationshipbetween the number of the internal radial cooling fins E₂′ and thenumber of the external radial cooling fins E₃″ is different than thatshown in FIGS. 3A-3B.

In FIGS. 3A-3B and 13A(1), the mid-plates E′ and E″ include otherfeatures that may not form part of the underlying invention per se,including outer retaining members E₅ configured with apertures E₅′ forreceiving fasteners (not shown), e.g., to couple the mid-plates E′ andE′ to some other part of the motor assembly, such as the motor frame MF(FIGS. 1 and 11), as well as including two or three outer retainingmembers E₆ configured with apertures E₆′ for receiving fasteners (notshown), e.g., to couple the mid-plates E′ and E″ to some other part ofthe motor assembly, such as the motor frame MF (FIGS. 1 and 11).

In effect, the mid-plate embodiments according to the present inventionset forth herein consist of a system having several highly engineeredelements:

By way of example, the motor assembly 10 may be configured with aspecially designed motor casing to improve thermal efficiency consistingof the following elements:

1) The mid-plate E, also called and known as a motor end-plate, may bemade of copper, aluminum, or cast iron, with the rear motor bearing orbearing housing H incorporated into the mid-plate E. The mid-plate E maybe optimized to conduct heat away from the pump's non-drive end bearing,the motor's stator S and rotor R, and insulate the electronics formingpart of the power plane P at the same time. This innovativeconfiguration according to the present invention would place the bearinghousing flange portion A inside the mid-plate E or E′ as shown in FIGS.1 and 11, and as such, the mid-plate E or E′ would effectively thenbecome the structural support for the rotor R.

2) The special heat sink fins E₂″, E ₃′ may be designed for low audiblenoise, and increased surface area, allowing for greater thermalefficiency.

3) Circular design unique geometry may be implemented to provideoptimized space and ease of manufacturing.

4) Circular geometry may be implemented that allows for configuration ofpower electronic modules (FIGS. 1 and 11) and electronics (FIGS. 2 and12A), which allows the rotor/shaft R to pass through to power thecooling fan F (FIGS. 1 and 11).

The mid-plate E or E′ may include one or more of the following:

-   -   The mid-plate E or E′ may be configured for housing the rear        motor bearing H;    -   The mid-plate E or E′ may be configured in relation to the power        plane component P;    -   The mid-plate E or E′ may be configured or incorporated with        bearing oil/grease tubes.    -   The mid-plate E or E′ may be configured so heat may be        redirected radially versus axially. The mid-plate E or E′ may        also be configured to use the radial cooling fins E₂′ to        redirect the heat from the motor end windings of the motor M to        the peripheral portion or edges E₃ of the mid-plate E or E′.    -   The mid-plate E or E′ may be configured to provide thermal paths        from the motor end windings to airflow on the outside of the        stator J.    -   The mid-plate E or E′ may be configured to provide a thermal        path for the rotor R to the ambient through the bearing assembly        H.    -   The mid-plate E or E′ may be configured to create and provide        the structural support for the rotor R.    -   The front B and rear C grease retainers may also be used in        conjunction with the mid-plate E or E′.    -   An integrated insulation layer G on the outside of this        mid-plate E or E′ limits the heat flow from the mid-plate        heat-sink to the power converter area and limits heat into the        end-plate electronics area.    -   Minimized thermal contact may be implemented between the        mid-plate E or E′ and the end-plate D via an insulating gasket G        that forms part of the gasket assembly GA.

Mid-Plate: Theory of Operation

The mid-plate E or E′ is configured with a unique design thatincorporates a circular geometry with internal and external heat sinkfins E₂′, E₃″, e.g., consistent with that shown in FIGS. 1 and 11. Theinternal fins E₂′ are located along the inner circumference E₁′ of themid-plate E or E′, leaving space in the center for the rotor bearinghousing H. The external fins E₃″ are spread across the entire outerdiameter/circumference of the mid-plate E or E′, allowing for externalconvection capability, e.g., consistent with that shown in FIGS. 1 and11.

The mid-plate E or E′ also features a thin insulation layer G on theelectronics side of the mid-plate E, which is smooth and has no fins,e.g., as shown in FIGS. 2A-2B. This thin insulation layer G will allowvarious configurations for power electronic modules and electronicswhile still allowing the shaft/rotor R to pass through to power thecooling fan F. The main function of this design is threefold. Themid-plate E or E′ acts as a structural support for the motor M and themotor's rotor R, a heat sink for the non-drive end, and a thermalinsulator for the electronics chamber, e.g., that forms part of theend-plate D.

Thermal conductors are usually made of metal, due to their higher levelsof thermal conductivity and ability to absorb heat. Therefore, by way ofexample, the mid-plate E or E′ may be made of either aluminum, copper,or cast-iron. These metals have higher levels of thermal conductivity,good structural rigidity and are cost effective as compared to otherexotic materials.

In operation, the mid-plate E or E′ achieves its function throughconduction and convection, where conduction is understood to be thetransfer of heat between solids that are in contact with each other, andwhere convection is understood to be the heat transfer between a solidand a fluid. Conduction will occur between the shaft/rotor R and themid-plate E or E′ thru the bearing housing H, while convection occursbetween the heat sink fins E₂′, E₃″ and the air.

In operation, air cooled heat sinks, e.g., like element E₃″ may act ascooling mechanisms. They conduct the heat from the object it is incontact with and transfer heat to the air through convection. Tofunction properly, the heat sink has to be hotter than the ambienttemperature and the surface area contact should be maximized to ensureefficient thermal transfer. In the context of the present motor casingdesign, the mid-plate E or E′ will conduct the heat generated from theelectrical and mechanical losses of the motor M to the outside ambientair.

The losses from the rotor R can be attributed to the electrical losses(e.g., resistive and eddy current) caused by current flow, e.g., throughaluminum bars located in the rotor R. These losses cause the rotor R torelease heat into the motor's air chamber as well as directly conductinto the shaft/rotor R. The mid-plate E or E′ will absorb this heat boththrough conduction from the shaft/rotor R through the bearing assembly Hinto the mid-plate E or E′, and via convection through the heat sinkfins E₂′ or E₃″ located in the motor's internal air chamber.

The purpose of the thermal insulator G is to reduce the rate of heattransfer between two solids/fluids. As a person skilled in the art wouldappreciate, insulators reduce all forms of heat transfer, which are, ormay take the form of: conduction, convection, and radiation. Thermalinsulators are usually made of material with high resistance to thermalconductivity, due to their ability to reject heat. Therefore, theinsulation layer will be made of either mica, fiberglass, thermoplastic,or some inexpensive material with a low level of thermal conductivityand good structural rigidity.

This design is incorporated in the mid-plate E or E′ through anadditional layer that is attached to the mid-plate E or E′, e.g., asshown in FIG. 2. This insulation layer G may be comprised of mica, orsome other optimal insulator, that acts as a thermal insulator for theelectronic components forming part of the power plane P. The insulationacts as a barrier from the losses coming from the motor M in order toredirect heat towards the heat sink fins E₂′ or E₃″. The mid-plate E orE′ also houses the bearing housing H, which in turn supports the rotorand motor shaft R.

The overall design of the mid-plate E or E′ makes it a novel elementserving a multitude of functions simultaneously. The mid-plate Emechanically supports the non-drive end of the motor M, and allows therotor R to spin due to the attachment of the shaft bearing contained inthe center of the mid-plate E or E′. The mid-plate E or E′ efficientlyconducts motor heat to the exterior of the motor body, allowing themotor M to run reliably at an efficient temperature. Thirdly, theinsulator G insulates the electronics from the elevated motortemperature, and allows components to operate at temperatures belowtheir maximum rating.

Advantages

Advantages of the present invention may include one or more of thefollowing:

1) Allows for the manufacture of an embedded electronic motor drive(e.g., a variable frequency drive) in power levels greater thancurrently produced in the prior art.

2) Allows for the manufacture of a variable speed motor in the samefootprint as current industrial motors at power levels greater thancurrently produced in the prior art.

3) Via both internal and external heat sink fins E₂′ or E₃″, themid-plate E provides a thermally conductive pathway for both the motorwinding heat, and non-drive end bearing heat.

4) Via the integrated insulation, the mid-plate E or E′ provides abarrier to prevent heat from the motor to pass through to the sensitiveelectronics.

5) Due to its compact size, the mid-plate E or E′ allows, e.g., a matrixconverter to be designed to be installed into hazardous locationscontaining corrosives, moisture, and Class 1, Division 2 hazardouslocations, as well.

FIGS. 4A-4B and 14: The End-plate D, D′

FIGS. 4A-4B shows the at least one plate in the form of an end-plate D,D′ having two sides, a fan side FS having a central portion D₁, anintermediate portion D₂, a peripheral portion D₃.

The central portion D₁ may be configured with an opening O to receiveand arrange the end-plate D, D′ in relation to the rotor R (FIGS. 1 and11).

The intermediate portion D₂ may be configured between an innercircumference D₁′ of the central portion D₁ and the peripheral portionD₃. The intermediate portion D₂ may include internal radial cooling finsD₂′ extending from the inner circumference D₁′ of the central portion D₁and diverging outwardly towards the peripheral portion D₃ to transferheat from the central portion D₁ to the peripheral portion D₃ allowingfor internal conduction heat capability.

The peripheral portion D₃ may include an outer circumferential surfaceD₃′ (best shown as indicated in FIG. 4B and 14B) having external radialcooling fins D₃″ diverging outwardly away from the end-plate D totransfer the heat to surrounding air allowing for external convectionheat capability.

FIG. 4B and 14B show a mid-plate side MPS of the two side, e.g., thatmay be a smooth side having a corresponding intermediate portionD_(2, 2) with no cooling fins.

The power plane P may include electrical components, includingelectronics of a variable frequency drive, and the end-plate D, D′ maybe configured so that the smooth side MPS is facing the power plane P,e.g., as shown in FIG. 2A. The electronics module EM may be arrangedbetween the power plane P and the smooth side MPS, e.g., as shown inFIG. 2A.

Consistent with that shown in FIGS. 4A and 14, the internal radialcooling fins D₂′ may be configured on and about the intermediate portionD₂ substantially uniformly and equidistantly spaced from one another.The external radial cooling fins D₃″ may be configured on and about theperipheral portion E₃ substantially uniformly and equidistantly spacedfrom one another. By way of example, and consistent with that shown inFIG. 4A, the end-plate D, D′ may be configured so that the internalradial cooling fins D₂′ extend and diverge outwardly towards and connectto the external radial cooling fins D₃″, as shown in FIG. 4A and 14A.However, the scope of the embodiment is not intended to be limited tothe number of the internal radial cooling fins D₂′, the number of theexternal radial cooling fins D₃″, or the numerical or physicalrelationship between the internal radial cooling fins D₂′ and theexternal radial cooling fins D₃″. For example, embodiments areenvisioned, and the scope of the invention is intended to include,implementations in which the number of the internal radial cooling finsD₂′ and the number of the external radial cooling fins D₃″ is greater orless than that shown in FIG. 4A and 14A. Embodiments are alsoenvisioned, and the scope of the invention is intended to include,implementations in which the physical relationship between the internalradial cooling fins D₂′ and the external radial cooling fins D₃″ isdifferent than that shown in FIGS. 4A-4B and 14, e.g., including wherethe internal radial cooling fins D₂′ and the external radial coolingfins D₃″ are not connected, as well as where the number of the internalradial cooling fins D₂′ is greater or less than the number of theexternal radial cooling fins D₃″, when compared to that shown in FIG. 4Aand 14A.

In FIGS. 4A-4B and 14, the end-plate D, D′ may include other featuresthat may not form part of the underlying invention per se, includingouter retaining members D₅ configured with apertures D₅′ for receivingfasteners (not shown), e.g., to couple the end-plates D, D′ to someother part of the motor assembly, such as the motor frame MF (FIGS. 1and 11), as well as including two or three outer retaining members D₆configured with apertures D₆′ for receiving fasteners (not shown), e.g.,to couple the end-plates D, D′ to some other part of the motor assembly,such as the motor frame MF (FIGS. 1 and 11).

In addition to that set forth above, and by way of further example, theseveral other highly engineered elements of the motor assembly 10 mayalso include the end-plate D, D′; and the specially designed motorcasing to contain electronics and improve thermal efficiency may alsoinclude:

-   -   The motor end-plate D, D′, e.g., may be made of a metal such as        aluminum. The end-plate D, D′ may be optimized to conduct heat        away from the electronics P and/or EM contained inside of the        end-plate envelope, e.g., by having an insulating gasket GA to        minimize thermal contact between the mid-plate E and the        end-plate D, D′.    -   Special heat sink fins D₂′, D₃″ may be designed for low audible        noise and increased surface area, allowing for greater thermal        efficiency.    -   Circular designed unique geometry may be implemented to provide        optimized space and ease of manufacturing.    -   Circular geometry may be implemented that allows for a        configuration of power electronic modules and electronics (FIGS.        2A-2B and 17C) that allows the shaft R to pass through to power        the cooling fan F.

End-Plate: Theory of Operation

The design of the end-plate D, D′ incorporates a circular geometry,which consists of forming an electronics housing chamber generallyindicated as D₇ on the mid-plate side and heat sink fins D₂′, D₃″ on thefan side of the end-plate D. (As shown in FIG. 4B, the electronicshousing chamber D₇ is formed a s a hollowed out intermediate portionbetween the central portion D₁ and the peripheral portion D₃ of theend-plate D, D′.) This design allows electronic components P, EM (FIGS.2A-2B) to be contained inside the electronics housing chamber D₇ of theend-plate D and provides ample cooling due to the heat sink fins D₂′,D₃″. The electronics housing chamber D₇ is integrated on one smoothmid-plate side of the end-plate D, D′, where the inner diameter ishollowed as shown in FIG. 4B to allow room for power electronic modulesand printed circuit boards to be installed. The heat sink fins D₂′, D₃″are formed on the fan side of the end-plate D, D′ in a radialarrangement extending from the motor shaft center or central portion D₁,extending outward and across the outer axial surface. The heat sink finsD₂′, D₃″ share the same basic pattern as those built on the bearingsupporting plate called the “mid-plate” E, E′. (FIGS. 3A-3B and 13). Theend-plate D, D′ also has room in the center to allow the shaft/rotor Rto pass through in order to power the cooling fan F (FIGS. 1-2B). Thefunction of the end-plate D, D′ is twofold: to act as a heat sink forthe waste heat emitting from the electronics, and a sealed enclosure toallow the electronic components a place to be mounted and protected fromharsh environments.

The end-plate D, D′ functions through both conduction and convection. Asa person skilled in the art would appreciate, and consistent with thatset forth above, conduction is the transfer of heat between solids thatare in contact with each other, and convection is the heat transferbetween a solid and a fluid. Conduction will occur due to the powermodules, e.g. EM, mounted to the inner face of the end-plate D, D′. Theelectronic printed circuit boards, and components will produce wasteheat while in operation. This heat will be absorbed by the end-plate'sheat sink characteristic. All heat will then be released by convectionthrough the fins D₂′, D₃″ and cooling fan F. Convection will mainlyoccur between the heat sink fins D₂′, D₃″ and ambient air.

As a thermal conductor, this design may work best when constructed ofmetal. This is due to their higher levels of thermal conductivity andability to absorb heat. Therefore, the end-plate D, D′ will typically bemade of a metal like aluminum. By way of example, this material waschosen for its structural rigidity, ability to conduct heat extremelywell, and cost effectiveness over other considerations, although thescope of the invention is intended to include other types or kind ofmetals either now known or later developed in the future.

The end-plate D, D′ may be mounted between the mid-plate E, E′ and thecooling fan F, as shown in FIGS. 1-2B and 5A-5D. Thermal contact betweenthe mid-plate E, E′ and the end-plate D, D′ is limited through thethermal insulator G, as shown in FIGS. 2A-2B. This shields theelectronics from waste heat coming from the motor and bearing. Theend-plate D, D′ as a whole acts as an enclosure for the components andprotects them from both harsh environments and excessive heat.

In addition to shielding the electronics from heat, this design is alsobe able to expel that heat into the ambient air and maintain viableoperating temperatures. This function is achieved by both the heat sinkfins D₂′, D₃″ and the cooling fan F. Since the fins D₂′, D₃″ are spreadalong the vast surface area of the end-plate D, D′; they have theability to conduct heat from the power modules, and air chamber to theoutside of the end-plate chamber. Once outside the end-plate chamber,the heat is removed by convection. The cooling fan F provides properairflow over the entire surface of the metal (e.g., aluminum) fins ofthe end-plate D, D′ and aids in maintaining the temperature of thecomponents below their maximum rating.

Heat sinks act D₂′, D₃″ as cooling mechanisms. They conduct the heatfrom the object it is in contact with and transfer heat to the airthrough convection. To function properly, the heat sink fin D₂′, D₃″ hasto be hotter than the ambient temperature and the surface area contactshould be maximized to ensure efficient thermal transfer. In terms ofthe end-plate D, D′, it will absorb the heat generated from both thepower modules and the air chamber of the variable frequency drive (VFD)and transfer it to the outside ambient air.

Overall, the design of the end-plate D, D′ allows it to serve multiplefunctions during operation. First, it provides a protective enclosure tocontain all of the electronics. Second, it acts as a heat sink to removeheat generated by the losses in the components, thereby protecting thecomponents from excessive temperatures. The unique geometry of theend-plate D, D′ allows these components to be placed in the sameenvelope as a standard electric motor rated for normally hazardousareas. Lastly, the heat sink fins D₂′, D₃″ and cooling fan F aid inhandling heat distribution throughout the end-plate D, D′. With all ofthese features, the end-plate D, D′ allows the electronics to runsmoothly during operation and maintain their temperature below themaximum rating.

Advantages

The advantages of this invention may include the following:

Via external heat sink fins D₂′, D₃″, the end-plate D, D′ provides athermally conductive pathway for the power module heat.

Allows for the electronic variable speed drive to be contained withinthe footprint of a current electric motor M.

Due to the compact size, it allows the power electronics to be installedinto hazardous locations containing corrosives or moisture

Allows for the manufacture of an embedded electronic motor drive inpower levels greater than currently produced

The power electronics will be housed in the motor end-plate D, D′ andsealed between the mid-plate E, E′.

The end-plate D, D′ design will permit easy removal from motor and easydisconnect of power and communication connections.

The combined end-plate/mid-plate design shall have IP66 protection. Allwiring/cable pass through to be sealed, static seals at mid-plate E tomotor M, end-plate D, D′ to mid-plate E, E′, end-plate power electronicsto be sealed at the outside diameter (OD) and the inside diameter (ID).Dynamic seal at shaft/mid-plate.

FIG. 5A to 5D

FIG. 5A and 5B shows the motor assembly 10 having the main terminal boxTB arranged thereon, which provides a sealed junction point for themotor, the motor drive, the drive interface and external power wiring,as well as a terminal box housing having power inductors PI arrangedtherein, as shown. The main terminal box TB includes a terminal boxcover TBC, a terminal box gasket TBG, and terminal box screws foraffixing the terminal box cover on the terminal box housing TBH.

FIG. 5C shows the motor assembly in an exploded view, which illustratesthe simplicity of the end-plate's (D) electrical and mechanicalconnection to the motor frame (MF). FIG. 5C also shows that theend-plate (D) is a complete self-contained drive module as shown in 5D,which provides portability to service in a suitable environment or for aquick replacement to a new end-plate(D) drive module, if the oldend-plate breaks down, which affords the overall motor assembly design a‘Plug and Play” style that is unique to the motor assembly art. by wayof example, FIG. 5C shows terminal box connector wires CW (e.g., whichcan be more or less wires than that specifically shown), a connectorcover CC, a connector hardware CH, a dust seal DS and end-plate mountinghardware MH.

FIG. 5D shows the self-contained drive module assembly, e.g., whichincludes the end-plate D, the terminal box TB, wire channels WC, theconnector cover CC, the connector cover hardware CCH, an electronicsmodule EM (see also FIGS. 7 and 10B), the end-plate covergasket/insulator GI, the end-plate cover EC and end-plate cover hardwareECH.

In summary, consistent with that shown in FIGS. 5C and 5D, the processfor disassembly the end-plate D is as follows:

-   -   1) remove the shroud hardware (not shown) and the shroud S (FIG.        5C),    -   2) remove fan set screw/hardware (not shown) and the fan F (FIG.        5C),    -   3) remove the connector cover hardware CCH and connector cover        CC,    -   4) disconnect the end-plate connector (not shown) from terminal        box connector wires TBCW,    -   5) remove the end-plate mounting hardware ECH and the        self-contained drive end-plate(D) module EM.        The self-contained drive end-plate(D) module EM can be replaced        and the end-plate D can be reassembled using the same steps.

FIGS. 6A-10B: The Power Plane P

According to some embodiments, the present invention disclosed hereinmay consist of a system or apparatus, e.g., having, or in the form of,the power plane P configured for providing power and controlfunctionality, e.g., for operating the motor assembly in order to drivea pump or rotary device. The power plane P features several highlyengineered elements, as follows:

By way of example, the power plane P may have a circular geometry to bemounted inside a space envelope SE (FIGS. 5D and 9B) having a similarcircular geometry formed on the end-plate D, D′ (e.g., see FIGS. 1,4A-4B, 9A-9B, 11, 14A-14B) between the inner hub portion D₁ and theperipheral portion D₃ that extends circumferentially around the spaceenvelope SE (aka the electronics housing chamber D₇ (see FIG. 4B, 5D and14B)) of the end-plate D, D′. The power plane P may be a multi-layercircuit board or assembly, e.g., having: a power layer, a control layerand a thermal barrier and printed circuit board layer P(1). The powerlayer includes higher temperature power modules like circular powermodules P/CM (e.g., see FIG. 17C) for providing power to the motor M,e.g., of the pump or rotary device. The control layer includes lowertemperature control electronics modules like power quality filtercapacitors IFC (e.g., see FIG. 17C) for controlling the power providedto the motor M. The thermal barrier and printed circuit board layer P(1)in FIGS. 10B in configured between the power layer and the control layerand provides electrical connection paths between the power modules ofthe power plane and the control electronics modules of the controllayer, and also provides thermal insulation between the power layer andthe control layer.

By way of example, the power plane P may be configured to do at leastthe following:

-   -   1) allow the mounting of the power modules like elements P/CM        (e.g., see FIGS. 10B and 17C) and the control electronics        modules like elements IFC (e.g., see FIGS. 10B and 17C) on        opposite sides of the thermal barrier, e.g., such as element        P(1) shown in FIG. 10B;    -   2) provide the electrical connection paths (e.g., see        connections C₁, C₂, C₃ and gate driver or layer connections GDC        in FIGS. 7 and 18B) for interconnecting together the power        modules like element P/CM and the control electronics modules        like element IFC, as well as for interconnecting input/output        power connections (see FIG. 18A re PEEK supports PS(2), re the        input phase connection, and re the input phase wire with        connection) and the power modules like element P/CM (e.g., see        FIG. 17C) and the control electronics modules like element IFC        (e.g., see FIG. 17C), and    -   3) insulate and/or direct heat emitted from one or more of the        power modules like element P/CM (e.g., see FIG. 17C), the        control electronics modules like element IFC (e.g., see FIG.        17C) and a shaft or rotor R of the motor M to the outer diameter        of the power plane where there is a higher air flow, e.g.,        consistent with that shown in FIGS. 9A and 9B.

The power plane P may be configured as a doughnut shaped power planeprinted circuit board or assembly like element P(1) in FIG. 10B in orderto fit in the space envelope SE of the end-plate D, D′ for providing amaximum space for mounting the power layer and the control layer, and toallow the shaft or rotor R to pass through to power the cooling fan F(see FIGS. 1 and 11).

The power layer may be configured with an arrangement of highertemperature power modules, e.g., like elements P/CM (FIG. 17C). Thecontrol layer may be configured with an arrangement of lower temperaturecontrol electronic components and power quality filter components, e.g.,like elements IFC (FIGS. 7 and 17C). The thermal barrier and printedcircuit board layer P(1) may be configured from a material having astructural thickness and strength to mount the control layer on one sideand the power layer on an opposite side. The fiberglass materialconfigured to provide insulation to reduce the transfer of heat betweenthe power layer and the control layer.

It is understood that the power layer and the control layer may includeother modules or components within the spirit of the present invention,e.g., consistent with that disclosed herein, including one or morecontrol cards, clamp capacitors, a gate driver power supply, etc., e.g.,as shown in FIG. 10B and 18B.

Theory of Operation

In effect, the power plane P (see also FIGS. 1 and 11) is a componentthat will be mounted inside the space envelope SE (e.g., see FIG. 17B)of the end-plate D, D′ (FIGS. 1 and 17B). It shares the same circulargeometry, which will allow the shaft or rotor R to pass through to powerthe cooling fan F (FIGS. 1 and 11). By way of example, the circulargeometry may take the form of, or be characterized as, doughnut-shaped,or disk-like, e.g., consistent with that disclosed herein. This willalso allow ease of manufacture and installation of its components. Thepower plane P consists of several elements, e.g., which are shown anddescribed in relation to

FIGS. 6A-10B. The elements may include matrix converter power modules,matrix converter control electronics, power quality filter capacitors,and a printed circuit board, e.g., consistent with that disclosedherein. The function of the power plane P is threefold:

-   -   (1) provide a novel geometry allowing the mounting of power        modules and control electronic components,    -   (2) provide an electric connection path for all modules and        components, including power modules and control electronic        components, mounted thereon, and    -   (3) insulate/direct heat emitted from all the electronic power        modules, control electronics and motor shaft R (FIGS. 1 and 11).

The matrix converter is the main system configured on the power plane P,e.g., that is represented as shown in FIGS. 6A-6B, which includes FIG.6A showing a diagram of a bi-directional switch, e.g., using IGBTtechnology for implementing the desired power functionality (FIG. 6A),and also includes FIG. 6B showing a photograph of an example of abi-directional switch power module for implementing the desired powerfunctionality. (As a person skilled in the art would appreciate, aninsulated-gate bipolar transistor (IGBT) is a three-terminal powersemiconductor device primarily used as an electronic switch which, as itwas developed, came to combine high efficiency and fast switching. Forexample, Infineon Technologies AG distributed various products usingsuch IGBT technology.) The purpose of having this circuit shown in FIG.6A is to allow the matrix converter to convert an AC input of fixedvoltage and frequency to a desired AC output waveform. Traditionally, inthe prior art input AC power would have to be converted to a DC waveformbefore being synthesized into an AC output. According to someembodiments of the present invention, the matrix converter may beconfigured to execute this process in fewer steps and with fewercomponents. Among the electronic modules, the power quality filter IFCmay be configured as a prominent component (see FIG. 7). In such a case,its function is to reduce the level of electrical noise and harmonicdistortions, e.g., consistent with that shown in FIG. 8. In someembodiments according to the present invention, this power qualityfilter component may be preferably attached directly onto the printedcircuit board, such as element P(1) to be as close to the matrixconverter as possible. This greatly improves its ability to reduce theamount of distortions emitted from the matrix converter electronics. Theoverall geometry and size of the power plane P allows for ease ofmanufacture and installation for power modules and control electronics.

In this power plane portion of the overall motor assembly shown in FIGS.1 and 11, heat will be emitted from at least two sources: the powersemi-conductor modules and the shaft or rotor R (FIGS. 1 and 11).Consistent with that set forth herein, the power semi-conductor modulesmay include one or more of the following: the circular power modulesarrangement shown in FIG. 17C or the power modules layout shown in FIGS.18A, power modules and clamp module layout in FIG. 10B or the layout ofthe power/clamping modules in FIG. 10B. Although the mid-plate E, E′(e.g., see FIGS. 1, 2A, 2B and 3A-3B; 11, 12A, 12B, 13A(1)-13B) may beconfigured with an insulation layer protecting the electronics, asdescribed above, there will likely still be residual heat from the shaftor rotor R. This is due to the temperature difference between the fanside and the mid-plate portion of the motor assembly (FIGS. 1 and 11).It is also understood that semi-conductors in the power plane P willnaturally generate heat during operation. The challenge is maintainingan operating temperature in order for the electronics to operateproperly, e.g., below the failure point of the electronics.

Therefore, insulation and dissipation of heat are two functions that thepower plane P must perform. The former regarding insulation is achievedthrough the multi-layered circuit board implementation disclosed herein.The multi-layered circuit board may be constructed of laminated materialsuch as fiberglass, by way of example, which increases its thickness andstrength. Fiberglass is known and understood to be a strong andlight-weight material which has been used for insulation applications.This allows the power plane P to act as a thermal barrier between hotterpower modules, the power quality capacitors and control electronics.

For the latter, heat will be dissipated through the heat sink fins D₂′and/or D₃″ (FIGS. 4A-4B and 14) located on the end-plate D, D′. The heatsink fins D₂′ and/or D₃″ will be air cooled and act as coolingmechanisms. They operate through conduction and convection, two forms ofheat transfer, where conduction is understood to be the transfer of heatbetween solids that are in contact with each other, while convection isunderstood to be the transfer of heat between a solid and a fluid. Heattransfer will first occur between the printed circuit board and thesemi-conductors. It will then travel into the end-plate D, D′ and heatsink fins D₂′ and/or D₃″. Lastly, convection occurs between the heatfins D₃″ and the ambient air, e.g., surrounding the overall motorassembly 10 (FIG. 1) dispersing the heat. To function properly, the finsD₃″ have to be cooler to absorb heat and be elevated to a hot enoughtemperature to diffuse it into ambient air. Since the power plane P alsoshares a similar geometry with the intermediate portion D₂ of theend-plate D, the heat will be distributed uniformly along the surface.

The overall configuration of this multi-purpose power plane P makes itan important contribution to the state of the art. The space envelope SE(FIGS. 4B, 5D, 17B) from the end-plate D, D′ allocates room for theoverall power plane P and allows it to support both power modules andcontrol electronics. In addition, the power plane P has access to theheat sink fins D₂′ and/or D₃″ from the end-plate D; enabling it to coolthe electronics at an operable temperature. The fiberglass circuit boardconstruction of layer or element P(1) acts as an excellent insulator;separating hotter power semi-conductors from the sensitive controlelectronics and power quality capacitors. These combined componentsallow the power plane P to facilitate operating conditions and maintainthe temperature of the control electronics well below maximumtemperature levels.

Advantages

Advantages of this power plane embodiment may include one or more of thefollowing:

The printed circuit board layer P(1) may be configured to act as athermal barrier between hotter power modules to the cooler controlelectronics and power quality capacitors area.

The overall power plane implementation may be configured so as to directheat to outer diameter where there is a higher air flow and away fromcontrol circuits, e.g., as best represented by that shown in FIGS.9A-9B.

The overall printed circuit board assembly provides a low inductance andresistance input between the power quality capacitors and the powersemiconductor modules, thereby reducing switching stress andelectromagnetic interference, e.g., consistent with that shown in thegraph in FIG. 8.

The overall power plane implementation may be configured with a uniquecompact power quality filter arrangement that is integrated into thepower plane P.

The overall power plane implementation may be configured with a built-inpower quality filter that produces minimal harmonic distortion, andprotects the variable frequency electronics from most power qualityabnormalities.

The overall power plane implementation may be configured with or as aunique doughnut shaped power plane printed circuit board (PCB), e.g.,shaped like element P(1), to fit in the space envelope SE of motorend-plate D providing for maximum space utilization, and simplifyingconstruction and manufacturing. (By way of example, see that shown FIGS.1 and 11, as well as that shown in FIGS. 7, 16 and 18B)

The doughnut shape allows the motor shaft or rotor R (FIGS. 1 and 11) topass through to power the cooling fan F.

The overall power plane implementation combines both power and controlmodules, circuits or components into one integrated printed circuitboard assembly, e.g., as shown in FIG. 18B, for ease of assembly andcompactness in size.

The overall power plane implementation provides interconnections forinput/output power, current sensors, gate driver GDPS, clamp controlcircuit CCs, power/clamp semi-conductor modules, power qualitycapacitors IFC, e.g. with limited wiring and connectors required, thusallowing for a robust and reliable operation.

The overall power plane implementation allows for the manufacture of anembedded electronic motor drive in power levels greater than thatcurrently produced in the marketplace and in the space envelope of anelectric motor.

The motor frame or casing MF (FIGS. 5A and 15) is effectively utilizedas a heat sink to allow compact size and thermally optimized operationof the power plane P and matrix converter configuration.

The Scope of the Invention

It should be understood that, unless stated otherwise herein, any of thefeatures, characteristics, alternatives or modifications describedregarding a particular embodiment herein may also be applied, used, orincorporated with any other embodiment described herein. Also, thedrawing herein is not drawn to scale.

Although the invention has been described and illustrated with respectto exemplary embodiments thereof, the foregoing and various otheradditions and omissions may be made therein and thereto withoutdeparting from the spirit and scope of the present invention.

We claim:
 1. A motor assembly, comprising: a motor housing; anelectrical motor within the motor housing; a rotor coupled to the motorand extending out of the motor housing along an axis; a driveelectronics housing mounted in-line with the motor housing, the driveelectronics housing comprising: a peripheral wall; and an interiorvolume bounded by an inner surface of the peripheral wall; and avariable frequency drive electronics unit disposed within the interiorvolume and configured to provide power to the motor, the variablefrequency drive electronics unit comprising: a circuit board; aplurality of power switching components mounted to a first side of theboard and arranged about a center of the circuit board; and a pluralityof power control components mounted to a second side of the circuitboard opposite the first side.
 2. The motor assembly of claim 1, whereinthe drive electronics housing is configured for removable mounting tothe motor assembly.
 3. The motor assembly of claim 1, wherein thevariable frequency drive electronics unit implements a matrix converterthat converts an AC input signal to a converted AC output signal.
 4. Themotor assembly of claim 1, wherein the plurality of power controlcomponents comprises a plurality of power quality filter componentsmounted to the second side of the circuit board about the center of thecircuit board.
 5. The motor assembly of claim 1, wherein the driveelectronics housing comprises heat fins configured to dissipate heatgenerated by the plurality of power switching components and theplurality of power control components.
 6. The motor assembly of claim 1,wherein the motor assembly drives a pump or rotary device.
 7. The motorassembly of claim 1 further comprising a mid-plate mounted in-line withthe motor housing between the motor housing and the drive electronicshousing, the mid-plate comprising a plurality of cooling fins configuredto direct heat to a periphery of the mid-plate.
 8. The motor assembly ofclaim 7, wherein the mid-plate has an opening configured to accept therotor, and the cooling fins are configured to direct heat generated byrotation of the rotor to the periphery of the mid-plate.
 9. The motorassembly of claim 8 wherein the drive electronics housing comprises anopening configured to accept the rotor, the motor assembly furthercomprising a cooling fan driven by the rotor, the drive electronicshousing between the cooling fan and the mid-plate.
 10. The motorassembly of claim 1 further comprising a mid-plate mounted in-line withthe motor housing between the motor housing and the drive electronicshousing, the mid-plate having an opening configured to receive the rotorand a motor bearing assembly.
 11. An apparatus, comprising: a driveelectronics housing configured for mounting in-line with a motorhousing, the drive electronics housing comprising: a peripheral wall;and an interior volume bounded by an inner surface of the peripheralwall; a variable frequency drive electronics unit disposed within theinterior volume and configured to provide power to the motor, thevariable frequency drive electronics unit comprising: a circuit board; aplurality of power switching components mounted to a first side of thecircuit board and arranged about a center of the circuit board; and aplurality of power control components mounted to a second side of thecircuit board opposite the first side.
 12. The apparatus of claim 11,wherein the plurality of power control components are arranged about thecenter of the circuit board.
 13. The apparatus of claim 12, wherein theplurality of power control components comprise power quality filtercomponents.
 14. The apparatus of claim 11, wherein the drive electronicshousing is configured for removable mounting.
 15. The apparatus of claim12, wherein the drive electronics housing is an end-plate configured forremovable mounting to a mid-plate, the mid-plate mounted in-line withthe motor housing between the motor housing and the end-plate.
 16. Theapparatus of claim 11, wherein the power switching components form partof a matrix converter.
 17. The apparatus of claim 11, wherein the driveelectronics housing comprises one or more channels for housing powerwires that extend between the variable frequency drive electronics unitand the motor when the drive electronics unit is mounted.
 18. A variablefrequency drive unit, comprising: a circuit board; variable frequencydrive electronics configured to provide a variable frequency power drivesignal for an electric motor, comprising: power switching electronicscomprising a plurality of power switching components mounted to a firstside of the circuit board and arranged about a center of the circuitboard; power control electronics comprising a plurality of power controlcomponents mounted to a second side of the circuit board opposite thefirst side; and one or more connection paths extending from the firstside of the board to the second side of the circuit board and configuredto electrically couple the power switching electronics and the powercontrol electronics, the board configured to provide thermal insulationbetween the power switching electronics and the power controlelectronics.
 19. The variable frequency drive unit of claim 18, whereinthe plurality of power switching components are arranged in a circulararrangement and the plurality of power control components are arrangedin a circular arrangement.
 20. The variable frequency drive unit ofclaim 19, wherein the plurality of power control components comprisepower quality filter components.
 21. The variable frequency drive unitof claim 18, wherein the circuit board comprises a circular periphery,and wherein the circuit board with the power switching components andpower control components mounted thereto is dimensioned to fit within acircular space envelope of a drive electronics housing.
 22. The variablefrequency drive unit of claim 18, wherein the power switching componentsform part of a matrix converter.